Method and composition for contemporaneously dimerizing and hydrating a feed having butene to produce a gasoline composition

ABSTRACT

Methods for producing alcohols and oligomers contemporaneously from a hydrocarbon feed containing mixed butenes using an acid based catalyst are provided. Additionally, methods for producing fuel compositions having alcohols and oligomers prepared from mixed olefins are also provided as embodiments of the present invention. In certain embodiments, the catalyst can include a dual phase catalyst system that includes a water soluble acid catalyst and a solid acid catalyst.

RELATED APPLICATIONS

This patent application claims priority to U.S. Provisional PatentApplication Ser. No. 61/554,347, filed on Nov. 1, 2011, and is acontinuation of U.S. patent application Ser. No. 13/665,438, filed onOct. 31, 2012, which are all incorporated by reference in theirentirety.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method for simultaneously producingbutene oligomers and butanol from a feed stream having butene. Morespecifically, the present invention relates to a method forsimultaneously dimerizing and hydrating a mixed butenes feedstock toproduce butene oligomers and butanols.

BACKGROUND OF THE INVENTION

Internal combustion engines are commonly used on mobile platforms, inremote areas or in lawn and garden tools. There are various types ofinternal combustion engines. Spark type engines compress volatile fuels,such as gasoline, before ignition. Compression type engines take in airand compress it to generate the heat necessary to ignite the fuel, suchas diesel.

Although hydrocarbon fuels are the dominant energy resource for suchengines, alcohols, especially methanol and ethanol, have also been usedas fuels. For example, in the 1970s, gasohol, a blend of mostly gasolinewith some ethanol, was introduced during the Arab oil embargo.Currently, the primary alcohol fuel is ethanol. In general, ethanol canbe blended into gasoline in various quantities, normally at up to about10%, which typically results in a higher octane rating than regulargasoline. Certain fuels being produced today primarily include alcohols,for example, E-85 fuel contains 85% ethanol and 15% gasoline, and M-85has 85% methanol and 15% gasoline. There are, however, several drawbacksto the use of ethanol, such as energy deficiencies (ethanol providesabout 39% less energy than gasoline), high blending RVP (at 10% ofblending, RVP=11 psi), and incompatibility with existing transportationfacilities.

Further limitations exist with respect to the use of grain-based fuels.For example, grain ethanol is expensive to produce. Producing sufficientquantities of grain ethanol to satisfy the transportation industry needsis not practical because food crops and feed crops are and have beendiverted into grain ethanol fuel production. In addition, on avolumetric basis, both methanol and ethanol have relatively low energycontents when compared to gasoline. For example, methanol contains about50,000 Btu/gal and ethanol contains about 76,000 Btu/gal, whereasgasoline contains about 113,000 Btu/gal.

Long chain alcohols can be used together with amines/anilines asinhibitors to prevent metal corrosion and rubber/plastics swellingscaused by the ethanol fuels. These long chain alcohols, such asdodecanol, can also be used as emulsifying agents. Mixed low costmethanol and ethanol can be used with long chain alcohols to formalcohol blended diesels or used as emulsifying diesel adjustors. Longchain alcohols, however, are relatively expensive to produce.Methanol-based and ethanol-based diesels also suffer from the drawbackthat other additives are required to maintain a minimum Cetane numbergreater than 40 and to assure the diesel burns efficiently, such as longchain alcohols, alkyl esters and fatty acids.

Some time ago, lead was added to gasoline to boost its octane rating,thereby improving the antiknock properties of gasoline. Lead use,however, has been eliminated in most countries from gasoline forenvironmental reasons. In response to the need to phase out lead,gasoline sold in the United States and other countries was blended withup to 15% volumes of an oxygenate, such as methyl-tertiary-butyl-ether(MTBE), in an effort to raise the octane rating and to reduceenvironmentally harmful exhaust emissions. Due to its harmful effects,however, the industry is now replacing MTBE with the use of fermentedgrain ethanol, but as discussed above, producing the necessaryquantities of grain ethanol to replace MTBE is problematic in specificregions.

Another additive that has been used in fuels is methylcyclopentadienylmanganese tricarbonyl (MMT). MMT has been a controversial gasolineadditive for many years that is able to increase octane, but alsoincreases emissions, which may have an adverse effect on health andexhaust catalytic conversion systems.

In lieu of these questionable additives having the various deficienciesdescribed above, certain alcohols (e.g., butanols), and di-isobutenes(DIBs) can be used as combustible neat fuels, oxygenate fuel additives,or constituents in various types of fuels. When used as an oxygenatefuel, the BTU content of butanols and di-isobutenes is closer to theenergy content of gasoline than many of the methanol or ethanol basedfuels, as shown in Table I. HHV (second column) refers to Higher HeatingValue, which is defined as the amount of heat released by combusting aspecified quantity of the fuel at 25° C. and returning the temperatureof the combustion product to 25° C., which takes the latent heat ofvaporization of water in the combustion products.

TABLE I Properties of Butanols as compared to Gasoline Energy RVPDensity 15% Blend Blend Hydro- HHV RVP v/v RON MON d(RON − Den. carbon(MJ/kg) RON MON (R + M)/2 (PSI) Blend (10%) (10%) MON) (g/cc) Gasoline45.58 95 85 90 7.5 7.5 95 85 10 0.75 Alkylate 42 95 87 92 2.6 2.6 99.196.1 3 0.70 DIBs 48.24 101.1 85.7 93.4 1.7 1.7 124 99.1 24.9 0.73 2-37.33 115 97 106 0.83 4-5 120 95 25 0.81 butanol t-butanol 37.33 115 89102 0.44 4-5 105 89 16 0.78 MTBE 37.96 118 102 110 8.21 9 118 102 160.74 Ethanol 29.85 129 102 115.5 2 15 112 95 17 0.79

Alcohols and DIBs can be prepared from olefins, or more specificallyi-butene. Unfortunately, until now, there have not been any olefinhydration processes in place that are particularly effective forconverting mixed olefins into alcohols, especially butenes intobutanols, while simultaneously dimerizing the part of mixed olefins intooligomers such as DIBs.

Hydration reactions of butenes to butanols are commercially important asthe products have several important industrial applications.Additionally, butanols have been deemed as a second generation fuelcomponent after ethanol. These butanols can also be used as solvents orchemical intermediates for the production of corresponding ketones,esters, ethers, etc.

Butanols produced through typical bio-routes are not produced byefficient processes and are not produced in large enough quantity tomeet the demanding needs of the butanol market. Hydration reactions,which are typically acid catalyzed, can be used, but it is costly.Because organic butenes have very low solubility in water, relativelystrong acids are often required to achieve the desired kinetics toconvert the butenes to alcohols. Other processes used to producebutanols are also expensive. For example, petrochemical routes toproduce mixed butanols by hydroformation and hydrogenation frompropylene and carbon monoxide can be extremely costly.

One conventional commercial method of production of secondary butylalcohol includes using a two step processes in which the n-butenes arereacted with excess sulfuric acid (e.g., 80%) to form the correspondingsulfate, which is then hydrolysed to SBA, as follows:n-C₄H₈+H₂SO₄→2-C₄H₉OSO₃H2-C₄H₉OSO₃H+H₂O→2-C₄H₉OH+H₂SO₄During this process, the sulfuric acid becomes diluted to about 35%concentration by weight and must be re-concentrated before it can bereused in the process. One advantage of the process is a high conversionrate. Many other problems, however, are typically associated with theuse of liquid catalysts. Among the problems includes the separation andrecovery of the catalyst, corrosion of equipment and installations, andthe formation of undesired byproducts, such as secondary butyl ether,isopropyl alcohol, C₅-C₈ hydrocarbons, and polymers. Some of theseby-products complicate the purification of SBA.

Cationic exchange resins and zeolites are potentially important acidcatalysts for olefin hydration and are known to offer substantialreaction rates in both polar and non-polar media. Attempts have beenmade to use sulfonated polystyrene resins that have been cross linkedwith divinyl benzene as catalysts for the hydration of olefins such aspropylene or butene. These types of catalyst systems may offer severalengineering benefits, such as ease in separation and provide anon-corrosive environment.

In spite of the currently available processes, there are currently noeffective routes to producing mixed butanols and DIBs economically.Furthermore, conversion rates of olefin hydration are low at less than10% per pass.

Thus, a need exists for processes and catalyst systems that allow forthe simultaneous direct catalytic hydration and oligomerization ofalkenes to alcohols and oligomers. It would also be beneficial if theprocesses and catalyst systems were both inexpensive and provided aroute to industrially useful alcohols and a convenient synthetic routefor the synthesis of alcohols in general.

Additionally, there is a need for a fuel additive or fuel that has anoctane rating that is comparable to gasoline and having increasedcombustion efficiency. There is also a need for a fuel that reducesharmful emissions and airborne soot when combusted, either in neat formor as a fuel additive.

Finally, there is a need to provide a fuel or fuel composition having anoctane rating and BTU value that is similar to gasoline, but wherein thefuel or fuel composition does not include the use of tetraethyl lead,MTBE, methanol, ethanol, or MMT. Additionally, it is desirable toprovide a fuel additive that lowers the Reid Vapor Pressure of the fuelat least as well as, but without the use of, MTBE. It is also desirablethat such fuels, fuel compositions, or additives include mixed alcoholsthat are produced from mixed olefin streams.

SUMMARY OF THE INVENTION

The present invention is directed to a method that satisfies at leastone of these needs. In one aspect, a method is provided for thesimultaneous dimerizing and hydrating of a hydrocarbon feed havingbutene. In one embodiment, the method includes the step of introducingthe hydrocarbon feed into a reaction zone in the presence of water and acatalyst under reaction conditions that are operable to oligomerize andhydrate the butene within the hydrocarbon feed to form a product stream,wherein the product stream comprises butanols and di-isobutenes (DIBs).

In one embodiment, the hydrocarbon feed can include mixed butenes. Inanother embodiment, the hydrocarbon feed can be a mixed butene streamthat includes at least two butene compounds selected from the groupconsisting of 1-butene, 2-cis-butene, 2-trans-butene, and isobutene. Inanother embodiment, the hydrocarbon feed can include at least 5% byweight isobutene. In another embodiment, the hydrocarbon feed can be alight olefin stream. In one embodiment, the catalyst can be a watersoluble acid. In another embodiment, the catalyst can be a waterinsoluble acid. In another embodiment, the reaction zone can include areactor having one or more reaction stages. In one embodiment, preferredreaction conditions include a reaction temperature between about 100° C.and 200° C. and a pressure of between about 20 bars and 120 bars.

In one embodiment, the method can include the step of removing DIB andbutanol from the product stream, such that the forward reaction is morefavorable than the reverse reaction. In another embodiment, the methodcan also include the step of combining at least a portion of the productstream with a gasoline stream to produce a gasoline composition havingan increased research octane number (RON) as compared with the gasolinestream.

In one aspect of the present invention, a gasoline composition isprovided. The gasoline composition comprising a fuel-grade gasoline; andan octane enhancing additive comprising mixed butanols and DIBs, whereinthe octane enhancing additive is prepared by contacting a mixed butenestream with a dual phase catalyst system and water under conditionsoperable to oligomerize and hydrate the butenes to form the octaneenhancing additive.

In certain aspects of the present invention, the octane enhancingadditive is present in an amount of between about 5 and 30% by weight ofthe gasoline composition. In certain aspects of the present invention,the gasoline composition has an increased RON and a decreased RVP,relative to the fuel-grade gasoline prior to being combined with theoctane enhancing additive comprising the mixed butanols and DIBs. Incertain aspects of the present invention, the dual phase catalyst systemcomprises a water soluble acid catalyst and a water insoluble acidcatalyst. In certain aspects of the present invention, the water solubleacid catalyst is an organic acid selected from acetal acid, tosylateacid and perflurated acetic acid. In certain aspects of the presentinvention, the water soluble acid catalyst is an inorganic acid selectedfrom HCl, H₃PO₄, and H₂SO₄. In certain aspects of the present invention,the water insoluble acid catalyst is selected from ion exchange resin,zeolite, and a supported acid.

In a second aspect of the present invention, method for preparing agasoline composition is provided. The method includes the steps ofproviding a fuel-grade gasoline; providing an octane enhancingcomposition, wherein said octane enhancing composition is prepared bycontacting a mixed butene stream with a dual phase catalyst system andwater under conditions operable to oligomerize and hydrate the butenesto form the octane enhancing composition; and combining the fuel-gradegasoline and octane enhancing composition, the octane enhancingcomposition comprising mixed butanols and DIBs to form the gasolinecomposition.

In certain aspects of the present invention, the octane enhancingcomposition is combined with the fuel-grade gasoline after preparationwithout further purification. In certain aspects of the presentinvention, the octane enhancing composition is present in an amount ofbetween about 5 and 30% by weight of the gasoline composition. Incertain aspects of the present invention, the dual phase catalyst systemcomprises a water soluble acid catalyst and a water insoluble acidcatalyst. In certain aspects of the present invention, the water solubleacid catalyst is an organic acid selected from acetal acid, tosylateacid and perflurated acetic acid. In certain aspects of the presentinvention, the water soluble acid catalyst is an inorganic acid selectedfrom HCl, H₃PO₄, and H₂SO₄. In certain aspects of the present invention,the water insoluble acid catalyst is selected from ion exchange resin,zeolite, and a supported acid.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood with regard to the followingdescription, claims, and accompanying drawings. It is to be noted,however, that the drawings illustrate only several embodiments of theinvention and are therefore not to be considered limiting of theinvention's scope as it can admit to other equally effectiveembodiments.

FIG. 1 shows a process flow diagram in accordance with an embodiment ofthe invention.

FIG. 2 is a graphical depiction of the impact on RON of a gasolineblended with MTBE compared to gasoline blended with an oxygen enhancingadditive.

FIG. 3 is a graphical depiction of the impact on RVP of gasoline blendwith MTBE compared to gasoline blended with an oxygen enhancingadditive.

DETAILED DESCRIPTION OF THE INVENTION

While the invention will be described in connection with severalembodiments, it will be understood that the description is not intendedto limit the invention to those embodiments. On the contrary, it isintended to cover all the alternatives, modifications and equivalents asmay be included within the spirit and scope of the invention defined bythe appended claims.

Diisobutenes (DIBs) or Isooctenes:

Diisobutenes include two isomers of 2,4,4-trimethyl-1-pentene and2,4,4-trimethyl-2-pentene.

Mixed Butenes:

Mixed butenes have four structural isomers, 1-butene, 2-cis-butene,2-trans-butene and isobutene. Optionally, other low olefins such asethylene, propylene and pentylenes could be present in the feed.

Mixed Butanols:

Mixed butanols include at least two compounds selected from 1-butanol,2-butanol, t-butanol and isobutanol. Preferred embodiments of thepresent invention include only 2-butanol and t-butanol.

The Major Compounds Derived from the Oligomerization of Mixed Butenes:

Di-isobutenes (DIBs), tri-isobutenes, dimer of isobutene and n-butenes,and trimer of isobutene and n-butenes can all be derived from theoligomerization of mixed butenes. Hydration products of the oligomersand further etherification can also result. Other possible products areknown for persons who are skilled in the art. DIB is a non-oxygenativefuel component with many advantages as a blending agent, such as higherRON, higher octane sensitivity or better anti-knock quality, higherenergy content compared to MTBE and alkylates, and/or lower RVP thanMTBE and ethanol. A preferred blending agent is a mix of DIB andbutanols. DIB and butanols produced in this process, individually and incombination, are suitable blending agents for fuel. DIB has a higherenergy content than t-butanol. Preferably the DIB to butanol ratio isbetween about 1:4 and about 1:2 with a mixed butanol feed streamcontaining i-butene in the range of about 25 mol % to about 35 mol %.

Oligomerization of Mixed Butenes:

Oligomerizations of mixed butenes include oligomerizations of all buteneisomers, preferably oligomerizations of isobutene and most preferablythe dimerization of isobutene. The oligomerization fraction can beextremely rich in dimers (isooctenes or DIBs), and can be added as suchto the gasoline cuts to give a very high quality gasoline.

Dimerization of Isobutene:

Major Compounds Derived from the Hydration of Mixed Butenes:

2-butanol and t-butanol can both be made from the hydration of mixedbutenes. Other possible products such as etherification products ofbutanols and butenes or butanols itself are known for person who skilledin the art. Butanols generally have good gasoline octane blendingcharacteristics and may be used in combination as petroleum additiveswith other oxygenates such as ethanol.

Hydration of Mixed Butenes:

Hydrations of butenes to butanols are commercially important reactionsas the products find several important industrial applications.Generally, the hydration of mixed butenes is normally selected to onlyproduce 2-butanol and t-butanol. Mixed butanols, primarily 2-butanol andt-butanol, can be used as oxygenative type premium gasoline additives.

Methods for producing alcohols and oligomers from butene and/or otherolefins, and the catalyst systems for making such products are providedas embodiments of the present invention. Additionally, methods forproducing fuel compositions that include mixed alcohols and oligomersprepared from butene and/or other olefins are also provided asembodiments of the present invention.

For example, in one embodiment of the present invention, a method forproducing alcohols and oligomers from olefins is provided. In thisembodiment, a mixed olefin feedstock is contacted with a dual phasecatalyst in the presence of water at the appropriate reaction conditionsto produce a product stream that includes oligomers and alcohols. Incertain embodiments, the mixed olefin feedstock is a mixed butenefeedstock, and the product stream includes DIBs and mixed butanols. Inone embodiment, the product stream that includes DIBs and mixed butanolscan be combined with a fuel component to produce the fuel composition.The fuel component of the fuel composition can be selected fromgasoline, diesel, jet fuel, aviation gasoline, heating oil, bunker oil,or combinations thereof. In certain embodiments, the resultant fuelcomposition will have an increased RON and reduced RVP, without thepresence of other chemicals that can have deleterious effects on theenvironment.

The source of the mixed olefin stream can vary. For example, in someembodiments of the present invention, the mixed olefin stream can be adischarge stream from an FCC unit or thermal cracking unit, a raffinatesstream from an MTBE process, a raffinates stream from a TBA process, asteam cracking process of liquified petroleum gas (LPG), or combinationsthereof. Various types of olefins can be included in the mixed olefinstream. For example, in certain embodiments, the mixed olefin stream caninclude a mixed butene stream. In another embodiment, the mixed olefinstream can include propylene, n-butylene, 2-butene, isobutylene,pentenes, hexenes, olefins having more than 6 carbons with at least twobutenes, or combinations thereof. Other olefins that can be used inembodiments of the present invention include ethylene, propene, butenes,pentenes, or other higher olefins. Other suitable sources for the mixedolefin stream and types of olefins will be apparent to those of skill inthe art and are to be considered within the scope of the presentinvention.

Most commercialized butene hydration processes are designed either withpure feeds, like 1-butene and iso-butene, or mixed feeds for selectiveiso-butene hydration. The process conditions are selected to maximizethe yield of either 2-butanol or yield of t-butanol within the limit ofthermal dynamics. Because both 2-butanol and t-butanol are valuableoxygenates and octane enhancers for fuels, certain embodiments of thepresent invention use a novel olefin hydration catalyst system that iseffective for the production of highly desired butanols, such as2-butanol and t-butanol, for gasoline components from cheap mixedbutenes.

In one embodiment, the catalyst can be a dual phase catalyst system forthe production of mixed alcohols from mixed olefins that includes awater soluble acid catalyst and a solid acid catalyst.

The dual phase catalyst systems of the present invention can include awater soluble acid catalyst and a solid acid catalyst. In certainembodiments, the water soluble acid can include an organic acid, aninorganic acid, or combinations thereof. In embodiments wherein thewater soluble acid is an organic acid, the organic acid can be selectedfrom acetal acid, tosylate acid, perflurated acetic acid, lactic acid,citric acid, oxalic acid, benzoic acid, or combinations thereof. Inembodiments wherein the water soluble acid is an inorganic acid, theinorganic acid can be selected from hydrochloric acid (HCl), phosphoricacid (H₃PO₄), sulfuric acid (H₂SO₄), hydrofluoric acid, heteropoly acids(H₃[P(W₃O₁₀)₄]), or combinations thereof. In certain embodiments,particularly suitable water soluble acid catalysts can include H₃PO₄ orH₃[P(W₃O₁₀)₄]. In certain embodiments, the solid acid catalyst can be anionic exchange resin, a zeolite, a supported acid, or combinationsthereof. An example of a suitable supported acid is phosphoric acidsupported on silica. In certain embodiments, particularly suitable acidcatalysts are ionic exchange resins, such as Dowex® 50 resin from DowChemical Company, Amberlyst® 15 resin from Rohm and Haas, or D008 seriesresin from KaiRui Chemical Co., Ltd., China. Optionally, phase transferagents, surfactants, or promoter catalysts can be added to aid in theolefin hydration reactions. Other suitable types of catalysts that canbe used as the water soluble acid catalyst or the solid acid catalystwill be apparent to those of skill in the art and are to be consideredwithin the scope of the present invention.

In certain embodiments, the water soluble acid catalyst and the solidacid catalyst can be mixed together to form the dual phase catalystsystem. The mixing of each component can occur prior to being added tothe reactor or the mixing can occur in the reactor. Other suitablemethods for preparing the dual phase catalyst system, such as layeringthe components of the catalyst system, will be apparent to those ofskill in the art and are to be considered within the scope of thepresent invention.

The amount of each catalyst can vary depending upon the mixed olefinstream being sent to the process. In certain embodiments, the weightratio of the water soluble acid catalyst to the solid acid catalyst canrange from about 0.01:1 to about 100:1 in the dual phase catalystsystem. In certain embodiments, the weight ratio of the water solubleacid catalyst to the solid acid catalyst is between about 4:1 and 1:4,alternatively between about 2:1 and 1:2. In certain embodiments, theweight ratio of the water soluble acid catalyst to the solid acidcatalyst is about 1:1. Other suitable amounts of each component of thedual phase catalyst system will be apparent to those of skill in the artand are to be considered within the scope of the present invention. Thewater soluble acid catalyst can be recovered together with water.

The dual phase catalyst system described herein is more effective toconvert a mixed olefin stream into mixed alcohols than currentcommercialized single catalyst systems, such as (1) solution processeswith sulfuric acid, and (2) solid catalysts with ionic exchange resins.The dual catalyst system described herein is particularly effective forthe production of “petro-butanols”, i.e. secondary butyl alcohol (SBA)and tertiary butyl alcohol (TBA), from mixed C₄ olefin streams of FCCunit or other thermal cracking units and reffinates of other processessuch as MTBE or TBA.

The methods and catalyst systems described herein can be used to producevarious types of alcohols and oligomers. For example, in one embodiment,the mixed alcohol stream can include butanols. In another embodiment,the mixed alcohol stream can include 2-butanol and t-butanol. The typesof alcohols produced will depend upon the type of olefins contained inthe mixed olefin stream and the types of catalyst systems selected.Other types of alcohol streams that can be produced using the processesand catalyst systems described herein will be apparent to those of skillin the art and are to be considered within the scope of the presentinvention.

The alcohols and oligomers in the product stream made in accordance withembodiments of the present invention can be used as a component in fuelcompositions or as a neat fuel composition. For example, in oneembodiment, a neat fuel composition can be prepared according to themethods described herein that includes a mixed butanol fuel having anoctane rating suitable for use in combustion or compression engines, forexample an octane rating of at least about 89. The mixture has a RONfrom 89-100. In another embodiment, a fuel composition that includes afuel component and a mixed butanol fuel is provided. Under currentstandards for fuel for combustion engines, the acceptable range forethanol blending is up to 15 vol %. Due to low Reid Vapor Pressure andhigher RON, the mixed butanol and DIB blend ratio used in fuel can be onpar with the range for ethanol blending. The constraints on the olefinratio in fuel may restrict the mixed butanol and DIB blend ratio tobelow 18 vol % and the oxygen contents level at about 3.75%. A blendratio of 18 vol % translates to between about 10 vol % and about 15 vol% of butanols. In an embodiment, the fuel component can includegasoline, diesel, jet fuel, aviation gasoline, heating oil, bunker oil,or combinations thereof. In an aspect, the mixed butanols can includen-butanol, 2-(+/−)-butanol, iso-butanol, tert-butanol, or combinationsthereof; or alternatively, 2-(+/−)-butanol and tert-butanol. In certainembodiments, the mixed butanols can include at least two butanolcompounds selected from the n-butanol, 2-(+/−)-butanol, iso-butanol,tert-butanol, or combinations thereof; or alternatively, 2-(+/−)-butanoland tert-butanol. The mixed alcohol streams made in accordance withembodiments of the present invention can be used in other types of fuelcompositions, as will be apparent to those of skill in the art and areto be considered within the scope of the present invention.

Using mixed butanols as oxygenate fuel additives or constituents or as aneat fuel has several benefits. There are increased combustionefficiencies and reduced emissions of harmful gases and airborne soot.Other benefits of the mixed olefin fuels are that the BTU energy contentis closer to the energy content of gasoline than that ofmethanol/ethanol based fuels. Butanols can be used as octane enhancersand replace tetra-ethyl-lead, MTBE, methanol, ethanol, MMT and otheroctane boosters without the negative environmental impacts. As anotherbenefit, butanols have low and stable Reid Vapor Pressure blendingcharacteristics and are much less corrosive than methanol/ethanol, whichenables them to be used by existing storage and transportationfacilities. Butanol based fuels can also be used in existing engineswithout modifications. Furthermore, butanols are low toxicity componentsand normally readily biodegradable.

Additionally, the DIBs that are produced simultaneously with thebutanols according to the methods described herein serve asnon-oxygenative, high energy content and low Reid Vapor Pressure (RVP)gasoline components. The product stream can be blended into a gasolinecut in an amount of about 1-35% by volume, alternatively between about5-30% by volume, alternatively between about 5-20% by volume,alternatively between about 5-12% by volume, alternatively between about8-15% by volume, alternatively between about 12-20% by volume, for usein any internal combustion engine. The mixed DIBs and butanols can alsohelp to meet future reductions on aromatics content in fuelcompositions. The combined use of butanols and DIBs helps to meet theoxygen content limits, while also satisfying a desired increase of RONand lower RVP.

Another advantage of various embodiments of the invention is the abilityto exclude a butene pre-separation step. A pre-separation step is notrequired because the process of the present invention does not requireseparation of butenes and butene isomers (1-butene, iso-butene and2-butenes) from other olefins. Mixed olefins can be directly hydrated tomixed alcohols without pre-feed separations. A further advantage is thatwhole fractions of butene streams can be utilized for the manufacture ofuseful fuel components, oxygenates and octane enhancers as the wholeproduct stream can be used as a fuel additive without the need foradditional separation of the product stream components. The productsfrom various embodiments of the processes described herein can be usedas replacements for or be complimentary of MTBE, ethanol, and alkylatesin gasoline without having to perform an expensive separation process.

A further advantage of certain embodiments of the present invention isthat the co-production of the DIBs provides a synergistic effect withthe productions of the butanols. For example, the butanols can enhancethe interactions between the acidic catalysts and iso-butene, therebyaiding the production of DIBs. Furthermore, butanol exhibits apreference for distributing itself within the DIB rich organic phase,thereby facilitating extraction of the butanol from the unreacted water.Consequently, continuous removal of the organic phase can shift thereversible reaction in the forward direction, thereby increasing theoverall reaction yields.

Another advantage of the dual phase catalyst system of the presentinvention is that the catalyst system can hydrate and oligomerize mixedolefins at higher conversion rates than are realized commonly usedcommercial catalysts. In certain embodiments, pre-separation of theolefins that is typically required with prior known methods is notrequired in the current invention. By using the methods and systemsdescribed herein, whole fraction of olefins, such as butenes, can beutilized as feedstock for the manufacture of useful gasoline additives.The lower RVP of butanols and DIBs allows for larger quantities ofhigher alkane additions, such as pentane, in gasoline.

A further advantage of the methods and systems described herein is thatthe whole product stream, particularly when the product stream includesmixed butanols, can be utilized as useful fuel components, oxygenates,and octane enhancers. The “petro-butanols” produced according to themethods described herein can then be used as replacements orcomplimentary of MTBE or ethanol in gasoline

The methods described herein can utilize multiple types of equipment.For example, in certain embodiments, the step of contacting the mixedolefin stream can occur in a multi-staged reactor system. In anotherembodiment, the step of contacting the mixed olefin stream can occur ina single reactor system. Other suitable types of process equipment thatcan be used in embodiments of the present invention will be apparent tothose of skill in the art and are to be considered within the scope ofthe present invention.

In FIG. 1, water supplied via line 2 is combined with hydrocarbon feedsupplied via line 4 in reaction zone 10, where the butenes withinhydrocarbon feed 4 become hydrated and oligomerize to create productstream removed via line 12, wherein product stream in line 12 containsbutanol and DIB. In a preferred embodiment, reaction zone 10 ismaintained at a temperature of approximately 150° C. and a pressure ofapproximately 70 bar. Product stream in line 12 can then be optionallypassed through heat exchanger 13 to reduce the temperature of productstream in line 12 to approximately 100° C. prior to entering flash drumdecanter 30. In one embodiment, flash drum decanter 30 reduces thepressure to approximately 30 bar. Flash drum decanter 30 aids in theremoval of unreacted water 34 to form dry product stream in line 32.Unreacted water can then be recycled back via line 34 into the processto be reused in reaction zone 10.

Dry product stream supplied via line 32 is then fed into recovery column40, where the butanol and DIB are separated from any unreacted buteneswhich are removed via line 42 to form final product stream exiting therecovery column via line 44. Final product stream in line 44 exits thebottom of recovery column 40, and unreacted butenes in line 42 exit thetop of recovery column 40. In one embodiment, the top of recovery column40 is operating at a temperature of approximately 75° C. and a pressureof about 9 bar. Unreacted butenes in line 42 can be cooled via heatexchanger 45 prior to being supplied to accumulator decanter 50. Ataccumulator decanter 50, any additional water in unreacted butenessupplied via line 42 can be removed and recycled back to reaction zone10 via line 54. Optionally, dry unreacted butenes in line 52 can then berecycled back to reaction zone 10 as well. Heat exchangers 5 and 7 canbe used to preheat water supplied in line 2 and hydrocarbon feedsupplied in line 4, respectively.

EXAMPLES

The following examples are given for the purpose of illustratingembodiments of the present invention. However, it is to be understoodthat these examples are merely illustrative in nature, and that theprocess embodiments of the present invention are not necessarily limitedthereto.

The following experiments were conducted at a pilot plant. The firstexample illustrates that DIBs and butanols can be producedsimultaneously. In the first example, isobutene was used as thefeedstream. The catalyst was Kairui Chemicals D008 (wet) with a total of157 g of catalyst being loaded into the reactor. The reactor wasmaintained at a temperature of approximately 150° C. and a pressure ofabout 70 bars. The isobutene feed had a flow rate of approximately 0.5mL/min. The water had a flow rate of approximately 0.1 mL/min. This flowrate therefore yields about a 1:1 molar ratio of water to isobutene. Theresults of the first experiment can be found in Table II and Table III,below:

TABLE II Product Distribution and Yields Butanol Oligomers ConversionButanol DIB Butanol/ Exp.# (g) (g) (%) yield yield DIB 1 197.3 191.6 3516.9 18.5 0.916 2 212.3 216.7 38 17.8 20.5 0.872 3 218.1 212.0 40 19.321.0 0.916 4 115.9 167.0 29 10.9 17.7 0.618 Average 36 16.2 19.4 0.841

Detailed organic layer composition identifications are listed in TableIII:

TABLE III Organic Layer Composition Group Area (%) Butenes 14.0T-butanol 36.0 C8-olefins (dimers) 43.0 Di-butylethers 2.0 C12-olefins(trimers) 5.0

The second example illustrates selective production of DIBs. In thesecond example, the feedstream was comprised of mixed butenes. Table IVbelow provides a summary of the feed composition. The catalyst wasKairui Chemicals D008 (wet) with a total of 157 g of catalyst beingloaded into the reactor. The reactor was maintained at a temperature ofapproximately 150° C. and a pressure of about 70 bars. The isobutenefeed had a flow rate of approximately 0.5 mL/min. The water had a flowrate of approximately 0.2 mL/min. This flow rate provided about a 2:1molar ratio of water to mixed butenes. In this example, most of thebutanols are dissolved in the water layer. Overall, the ratio oforganics including DIBs, ethers, and C12 olefins to butanols is given inTable V. The results of the second experiment can be found in Table IVand Table V. The composition of the resulting organic layer is providedin Table VI.

TABLE IV Feed Composition for Second Experiment 1-Butene 21 2-CIS Butene19 2-Transbutene 25 i-butene 35

TABLE V Production Yield Butanol Oligomers Butene Exp.# (g) (g) Water(g) Conversion (%) 1 15.94 9.81 218.05 10.8% 2 14.65 9.63 206.12 10.9% 311.24 12.88 341.08 8.4% 4 11.10 12.74 325.16 8.9% 5 35.85 26.26 785.8911.2% 6 58.87 56.95 1280.48 11.5% 7 29.07 29.92 637.02 10.4%

TABLE VI Organic Layer Composition for Second Experiment Group Area (%)Butenes 11.3 T-butanol 0.9 2-butanol 0.8 C8-olefins 72.3 (dimers)Di-butylethers 2.4 C12-olefins 12.2 (trimers)

The third example illustrates the production of butanol in 2-phases, onein aqueous and one in organic. In this example, the feedstream wascomprised of mixed butenes. Table VII below provides a summary of thefeed composition. The catalyst was Kairui Chemicals D008 (wet) with atotal of 161 g of catalyst being loaded into the reactor. The reactorwas maintained at a temperature of approximately 150° C. and a pressureof about 70 bars. The mixed butene feed had a flow rate of approximately1.225 mL/min. The water had a flow rate of approximately 0.4 mL/min.This flow rate provided about a 1.7:1 molar ratio of water to mixedbutenes. The results of the third experiment can be found in Table VIII.The composition of the resulting organic layer is provided in Table IX.In this example, the product contained an aqueous layer containing 18 wt% t-butanol and an organic phase containing 42 wt % t-butanol. Theliquid product composition was about 50 wt % aqueous and 50 wt %organic.

TABLE VII Feed Composition 1-Butene 21 mol % 2-CIS Butene 19 mol %2-Transbutene 25 mol % i-butene 35 mol %

TABLE VIII Product Composition Butanol Butanol wt % Butanol wt % in aq.Oligomers in organic Butene Exp.# (g) Phase (g) phase Water (g)Conversion (%) 1 68.38 14% 58.30 26% 292.82 27.57% 2 115.23 13.5%  111.91 24% 510.42 24.08% 3 73.87 14% 66.51 27% 293.54 23.77%

TABLE IX Oligomer Composition Group Area (%) T-butanol 14 2-butanol 11.7C8-olefins, Di- 74.3 butylethers, C12-olefins

For the previous examples, the reaction conditions were in the range oftypical reaction conditions for commercial n-butene hydration reactions.The difference between the examples' and typical reactions was thelonger residence time in the examples, which promotes the formations ofDIBs.

The fourth and fifth examples illustrate the effect feed composition hason the product stream composition. The feed compositions included mixedbutenes and butanes, as shown in Tables X and XII below. The source ofthe feed stream was a naphtha based steam cracker. The change incomposition of the feed was due to changes in the severity of the steamcracker operating conditions and the composition of the feedstock. Thefeed composition assumes a C₄ splitter upstream of the hydrationreactor. In both examples, the catalyst, temperature, and pressure werekept constant. Therefore, any difference in the product streamcomposition was due to the difference in feed composition. Importantly,the examples show that the concentration of each component in the feedcomposition affects the product composition even if the overall mix ofcomponents remain the same, i.e., the mix of 1-butene, cis 2-butene,trans 2-butene, 2-butanol, i-butene, tert-butanol and DIBs. In otherwords, the examples show that changes in the butene isomer compositionresults in changes to the product composition. Unlike the examplespreviously, which were based on a once through pilot plant where theproduct was being collected without separating the water. The fourth andfifth examples were conducted in an integrated pilot plant that includeddownstream separation equipment such as distillation columns whichenabled separation of the product compositions from the water phase.

TABLE X Feed Composition Fifth Example The feed compositions are inweight %. 1-Butene 29.37% 2-CIS Butene 13.14% 2-Transbutene 23.05%i-butene 33.66% iso-Butane  0.08% n-Butane  0.70%

The feed composition in Table X produced an example of an oxygenenhancing composition having the composition in Table XI.

TABLE XI Oxygen Enhancing Composition 1 Component Weight % ButenesDi-iso Butene 1 3.43 Di-iso Butene 2 1.24 T-butanol 28.84 2-butanol63.47 Di Sec-Butyl Ether 1.98 C12-Olefins 0.10 C8-Oxygenate/Dibutyl 0.42ether Water 0.52

TABLE XII Feed Composition Sixth Example 1-Butene 36.90% 2-CIS Butene23.58% 2-Transbutene 23.44% i-butene 12.86% iso-Butane  1.23% n-Butane 2.00%

The feed composition in Table XII produced an example of an oxygenenhancing composition having the composition in Table XIII.

TABLE XIII Oxygen Enhancing Composition 2 Component Weight % ButenesDi-iso Butene 1 6.93 Di-iso Butene 2 4.55 T-butanol 17.07 2-butanol68.76 Di Sec-Butyl Ether 2.00 C12-Olefins 0.10 C8 -Oxygenate/Dibutylether 0.40 Water 0.20

As can be seen in table XIV, no substantial difference in fuelproperties was observed between oxygen enhancing composition 1 andoxygen enhancing composition 2.

TABLE XIV Fuel properties of oxygen enhancing compositions 1 and 2 fuelOxygen Oxygen Enhancing Enhancing Fuel Property Composition 1Composition 2 RON 104 106.7 MON 94.2 96 RVP (psi) 1.67 1.67 EnergyDensity (MJ/kg) 37.8 37.8

The seventh and eighth examples further illustrate the effect of feedcomposition on product composition. The seventh and eighth examples arebased on simulation models validated by the experimental results inexamples 5 and 6.

The feed stream in the seventh example is a C₄ stream from a naphthacracker after butadiene extraction, where no C₄ splitter is assumed.

TABLE XV Feed Composition Seventh Example 1-Butene 27.4% 2-CIS Butene 5.4% 2-Transbutene  9.0% i-butene 44.6% iso-Butane  5.2% n-Butane  8.1%

The feed composition in Table XIV produced a simulated product havingthe composition in Table XV.

TABLE XVI Simulated Product Composition 1 Component Weight % ButenesDi-iso Butene 1 11.6 Di-iso Butene 2 5.6 T-butanol 24.2 2-butanol 56.6Di Sec-Butyl Ether 1.0 C12-Olefins 0.10 C8-Oxygenate/Dibutyl ether 0.50Water 0.50

The feed stream in the eighth example is a C₄ stream from a FluidCatalytic Cracking (FCC) Unit that cracked naphtha and cycle oil, wherethe feed stream is after butadiene extraction, as in the seventh exampleno C₄ splitter assumed.

TABLE XVII Feed Composition Eighth Example 1-Butene 13.6% 2-CIS Butene13.9% 2-Transbutene 20.5% i-butene 17.2% iso-Butane 25.3% n-Butane  8.4%

The feed composition in Table XVII produced a simulated product havingthe composition in Table XVIII.

TABLE XVIII Simulated Product Composition 2 Component Weight % ButenesDi-iso Butene 1 5.2 Di-iso Butene 2 2.3 T-butanol 11.5 2-butanol 79 DiSec-Butyl Ether 1.0 C12-Olefins 0.10 C8-Oxygenate/Dibutyl ether 0.40Water 0.50

The examples herein illustrate the ranges of the different componentsthat can be in the oxygen enhancing additive product stream.

TABLE XIX Range of Product Composition Component Composition, wt %2-butanol 50-80% T-butanol 15-30% Di-iso Butene 1  1-10% Di-iso Butene 2 1-10% Di Sec-Butyl Ether 0-2% C12-Olefins   0-0.5% C8-Oxygenate/Dibutylether   0-0.5% Water 0.2-0.5%

A comparison of the fuel properties of the product compositions to MTBE,see Table I herein, shows that the RON and MON for the oxygen enhancingcompositions of the fourth and fifth examples are lower, but stillcomparable. In contrast, the RVP value of the oxygen enhancingcompositions is much lower than the value for MTBE, 1.67 psi compared to8.12 psi. The significantly lower RVP of the oxygen enhancingcompositions can allow for increased flexibility to add lower value highRON butane stream to the gasoline pool. Butane is an inexpensiveadditive that can be added to a gasoline blend to increase the RON up tothe regulated values, however it has a high RVP (52 psi), therefore, thecompositions of the present invention with low RVP allow for increasedability to blend in butane to increase RON. Tables XX shows differentfuel compositions having varying levels of additives, all compositionsare in volume %. Compositions 2 and 3 in Table XX indicates that fuelcompositions that include an oxygen enhancing composition as an additivehave increased T50 and T90 values that will make the fuel heavier, whichwill in turn enable the refinery to add lighter low value components.

TABLE XX Fuel compositions of blended fuels Component Composition 1Composition 2 Composition 3 Gasoline 85.32% 86.50% 80.70% MTBE 14.68% 0.00%   15% Oxygen Enhancing Composition 2    0% 13.50%  4.30%

TABLE XXI Fuel properties for blended fuels having the compositions inTable XV Fuel Properties Composition 1 Composition 2 Composition 3 RON95.3 91.7 95.4 MON 85.8 80.9 84.1 (RON + MON)/2 90.6 86.3 89.8 TotalOxygen, wt %  2.47%  2.86%  3.15% Total Olefins, vol %  5.70% 18.70%   8% Aromatics, vol % 27.50% 26.10% 25.50% T50, °F 203 252 214 T90, °F811 864 814 E200, %   48%  15.%   41% E300, %   84%  77.%   83%

FIG. 2 is a graph showing the effects on RON of adding the differentadditives, MTBE or the oxygen enhancing composition, to a fuel. TheExample 85 RON gasoline is a gasoline fuel having a RON of 85. TheExample 85 RON gasoline was blended with 5% to 25% volume of MTBE and 5%to 25% volume of oxygen enhancing composition and the RON value wasextrapolated for each of the compositions (BRON refers to the blendingRON).

FIG. 3 is a graph showing the effects on RVP of adding the differentadditives, MTBE or the oxygen enhancing composition, to a fuel. TheExample 90 RON gasoline is a gasoline fuel having a RON of 90. TheExample 90 RON gasoline was blended with 5% to 25% volume of MTBE andseparately 5% to 25% volume of oxygen enhancing composition and the RVPvalue of the blended fuel was plotted on the graph.

While the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives,modifications, and variations will be apparent to those skilled in theart in light of the foregoing description. Accordingly, it is intendedto embrace all such alternatives, modifications, and variations as fallwithin the spirit and broad scope of the appended claims. The presentinvention may suitably comprise, consist or consist essentially of theelements disclosed and may be practiced in the absence of an element notdisclosed. Furthermore, language referring to order, such as first andsecond, should be understood in an exemplary sense and not in a limitingsense. For example, it can be recognized by those skilled in the artthat certain steps can be combined into a single step.

The singular forms “a”, “an” and “the” include plural referents, unlessthe context clearly dictates otherwise.

Optional or optionally means that the subsequently described event orcircumstances may or may not occur. The description includes instanceswhere the event or circumstance occurs and instances where it does notoccur.

Ranges may be expressed herein as from about one particular value,and/or to about another particular value. When such a range isexpressed, it is to be understood that another embodiment is from theone particular value and/or to the other particular value, along withall combinations within said range.

We claim:
 1. A method for preparing a gasoline composition, the methodcomprising the steps of: providing a fuel-grade gasoline; providing anoctane enhancing composition, wherein said octane enhancing compositionis prepared by contacting a mixed butene stream with a dual phasecatalyst system and water under conditions operable to oligomerize andhydrate the butenes to form the octane enhancing composition; andcombining the fuel-grade gasoline and octane enhancing composition, theoctane enhancing composition comprising mixed butanols and DIBs to formthe gasoline composition.
 2. The method of claim 1 wherein the octaneenhancing composition is combined with the fuel-grade gasoline afterpreparation without further purification.
 3. The method of claim 1wherein the octane enhancing composition is present in an amount ofbetween about 5 and 30% by weight of the gasoline composition.
 4. Themethod of claim 1, wherein the dual phase catalyst system comprises awater soluble acid catalyst and a water insoluble acid catalyst.
 5. Themethod of claim 4, wherein the water soluble acid catalyst is an organicacid selected from acetal acid, tosylate acid and perflurated aceticacid.
 6. The method of claim 4, wherein the water soluble acid catalystis an inorganic acid selected from HCl, H3PO4, and H2SO4.
 7. The methodof claim 4, wherein the water insoluble acid catalyst is selected fromion exchange resin, zeolite, and a supported acid.